The Immunology Core provides basic HIV-related immunologic tests to researchers in the NYU CFAR. It is directed by Dr. Susan Zolla-Pazner, whose laboratory has been performing immunologic assays since the beginning of the AIDS epidemic in 1981. This core laboratory has grown to meet the needs of various researcher within CFAR. For example, HIV testing by ELISA and Western blot is offered as is testing of indeterminant specimens by radioimmunoprecipitation, upon request. p24 antigen testing is also offered; while this is not a component of standard work-ups, it has found usefulness in projects that require the identification of patients with significant viremia. Other immunologic assays include quantitation of beta-2 microglobulin and various cytokines which may be important in the immune regulation of HIV infection. Flowcytometry analysis is offered on routine blood specimens as well as on bronchoalveolar lavage specimens and research specimens that require special stains and analytic procedures. Several new assays are contemplated in the new CFAR. These include proliferative assays for lymphocyte activity against various antigens, assays for natural killer cell activity, and quantitation of antibody activity against various pathogens (hepatitis C, HTLV-I or II, etc.). In addition, B-cell precursor frequency assays will be offered. This laboratory is already fully equipped. Costs for supplies will be recovered by a charge-back system which is already in place.